In vitro digestibility and in vivo glucose response of native and physically modified rice starches varying amylose contents.

The native and physically modified rice starches with varying amylose contents were subjected to investigate the in vitro digestibility and the in vivo glucose tolerance in mice. The amylose and resistant starch (RS) contents of five native rice starches ranged in 4.7-30.6% and 6.3-11.8%, respectively. The RS contents of rice starches increased to 18.5-23.9% after heat-moisture treatment (HMT) and to 19.5-26.9% after annealing treatment (ANN). The heat-moisture and annealing treatments significantly reduced glycemic index (GI) values of the rice starches. GI values of the native, heat-moisture treated and annealed rice starches ranged in 68.9-100, 61.2-88.9 and 21.2-43.9, respectively. There was no correlation between amylose contents and the RS contents or GI values, while a strong negative correlation between RS contents and GI values was found (R(2)=-0.747, P<0.01).